Hydrogenation primary coal liquids

Fuel Hydrogen for PAFC power plants will typically be produced from conversion of a wide variety of primary fuels such as CH4 (e.g., natural gas), petroleum products (e.g., naphtha), coal liquids (e.g., CH3OH) or coal gases. Besides H2, CO and CO2 are also produced during conversion of these fuels (unreacted hydrocarbons are also present). These reformed fuels contain low levels of CO (after steam reforming and shift conversion reactions in the fuel processor) which cause anode poisoning in PAFCs. The CO2 and unreacted hydrocarbons (e.g., CH4) are electrochemically inert and act as diluents. Because the anode reaction is nearly reversible, the fuel... 

In an alternate version of the process ( 7), designated SRC-II, a portion of the coal solution is recycled as solvent in place of the distillate solvent of the SRC-I process. The filtration step is eliminated and, typically, the process operates at a higher pressure, higher temperature, and longer residence time than the SRC-I process. Hydrogen consumption and the conversion of dissolved coal is increased, and the primary product is a liquid rather than the solid product of the SRC-I process. The liquid product of the SRC-II process is the feedstock that is the subject of the work described in this chapter. 

Hydrocarbonization processes are characterized by three primary independent variables - temperature, hydrogen pressure, and coal type - and five other, important independent variables -solid residence time, gas residence time, reactor configuration, coal pretreatment, and catalyst impregnation. Control of these variables permits control, over a wide range, of (1) the relative yields of liquid, gaseous, and solid products, (2) the quality of one or more of these products, (3) hydrogen consumption, and, ultimately (4) product cost. 

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